1. Field of the Invention
The present invention relates to a centrifugal pump system having an integrated heat barrier. More particularly, the present invention relates to a centrifugal pump having a rigid structure integrated heat barrier which does not include external or internal cooling provisions.
2. Discussion of the Related Art
Conventional centrifugal pumps include heat barriers for providing a means of cooling. An example of such a centrifugal pump is disclosed in German Patent No. DE 3016681 C2. The heat barrier is designed as a subassembly whereby the heat barrier constitutes a structural component having a substantial axial length and is provided with two flange-mounting surfaces, one on the pump side, the other on the motor side. In the area of an impeller drive shaft, the heat barrier is provided with a pressure-resistant junction. Various inserts are positioned between the flanges to transfer the forces between the flange surfaces, while at the same time, their thermally reflective surfaces enable cooling.
The above described heat barrier, while effective in terms of heat attenuation, suffers from the drawback that it has a substantial axial length which negatively affects the vibration characteristics of the overall pump assembly. Further, since the interchangeable heat-attenuating elements of prior art heat barriers are mounted on a considerably smaller diameter than the force-transferring connectors between the pump and motor components and in view of today's significantly greater pump throughput parameters, this type of design negatively affects the vibration characteristics of the pump assembly.
An alternative centrifugal pump design is disclosed in G.B. Patent No. 936,727 in which the intake and output pressure connections are located in direct proximity to the heat barrier and are integrated into the wall separating the pump and motor sections. This results in large metal-to-metal contact surfaces between the pump and motor sections which are connected to one another and with a motor bearing bracket clamped between the pump and motor sections. Further, a disk-shaped space in the partitioning wall incorporating intake and exit connections contains an insulating layer which functions as a heat barrier. However, due to the large metal-to-metal contact surfaces and the inevitably resulting direct heat conduction, this type of heat barrier requires supplementary liquid cooling, which increases the complexity as well as cost of the pump system.
Accordingly, it is an object of the present invention to overcome the above mentioned shortcomings by providing a heat barrier which permits a rigid structural design of a centrifugal pump system without requiring supplemental external or internal cooling provisions.